1. Technical Field
The present invention relates to a device inputting data to a computer system, and more particularly to a pointing device inputting pointing data to a portable computer system.
2. Related Art
Computer systems are information handling systems that are utilized by many individuals and businesses today. A computer system can be defined as a microcomputer that includes a central processing unit (CPU), a volatile memory, a non-volatile memory, a display monitor, a keyboard, a mouse or other input device such as a trackball, a floppy diskette drive, a compact disc-read only memory (CD-ROM) drive, a modem, a hard disk storage device, and a printer. Typically, a computer system's main board, which is a printed circuit board known as a motherboard, is used to electrically connect these components together.
Portable computers are often referred to as laptop, notebook, or subnotebook computers. These computers typically incorporate a flat panel display such as a liquid crystal display (LCD) or other relatively small display. Portable computers also often provide for coupling to a conventional standalone display monitor and also often provide for coupling to an external input device such as an external mouse or trackball.
A computer is usually equipped to use a "mouse" for movement of a cursor and initiating other functions of the computer. The mouse has a rotatable ball and is known as an input device which is also a pointing device. Typically, one pointing device is provided as the input device for a portable computer. For example, a portable computer may include a trackball input device incorporated in the housing of the portable computer. Or the portable computer may include a touchpad input device incorporated in the housing of the portable computer. The trackball input device is a pointing device since it inputs pointing data or positional coordinate data to the computer. The touchpad input device is also a pointing device.
Problems that can occur include the following. Since these input devices are fixedly mounted to the housing of the portable computer, errors can occur due to unintentional touching of the input device. Also, a user may be accustomed to using a trackball and may prefer to use a trackball in lieu of a touchpad. However, if a particular portable computer includes only a touchpad, that user must use the touchpad, even though that device is not the preferred input device.
Exemplars of recent efforts in the art include U.S. Pat. No. 5,793,359 for a System For RF Communication Between a Computer And a Remote Wireless Data Input Device issued to Ushikubo, //U.S. Pat. No. 5,726,684 for a Detachable Convertible Mouse-Trackball Pointing Device for Use with a Computer issued to Blankenship et al., U.S. Pat. No. 5,546,334 for a Notebook Computer System with a Separable Trackball issued to Hsieh et al., U.S. Pat. No. 5,428,368 for a Combination Mouse and track Ball Unit issued to Grant, and U.S. Pat. No. 4,754,268 for a Wireless Mouse Apparatus issued to Mori.
While these recent efforts provide advantages, I note that they fail to adequately address how an improved input unit including two types of pointing devices can be provided conveniently and efficiently at a computer system, thereby adding versatility to the computer system.